RFR: 8295223 JFR: At most one native periodic event thread at a time

Hi, Could I have a review of PR that ensures only one Java thread calls into native to emit periodic events at a time. Testing: tier1-tier3, test/jdk/jdk/jfr Thanks Erik ------------- Commit messages: - Remove accidentally added file - Initial Changes: https://git.openjdk.org/jdk/pull/10676/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10676&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8295223 Stats: 21 lines in 2 files changed: 18 ins; 0 del; 3 mod Patch: https://git.openjdk.org/jdk/pull/10676.diff Fetch: git fetch https://git.openjdk.org/jdk pull/10676/head:pull/10676 PR: https://git.openjdk.org/jdk/pull/10676